(57) A current detection resistance such as a metal resistance is formed in series with
a power transistor, and in response to an output voltage of the current detection
resistance, an overcurrent protective circuit performs an overcurrent suppressing
operation with high accuracy without being affected by irregularity of a current multiplication
factor, etc.; thus, it is possible to realize a smaller chip area so as to reduce
the cost. Furthermore, a short-circuit protective circuit returns a terminal voltage
of a referenced resistance, that appears in accordance with a partial pressure value
of an output voltage, at the transistor, a partial pressure resistance, and a current
mirror circuit. And the short-circuit protective circuit controls a potential of a
base resistance and suppresses a base current. Hence, it is not necessary to dispose
the transistor for suppressing a current between base lines, so that a low-voltage
operation can be realized. In a direct-current stabilization power supply device having
a two-chip structure of a PNP power transistor and a control IC, it is possible to
achieve a smaller chip area and a low-voltage operation.
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